1. Field of the Invention
The present invention relates to a head protecting airbag device whose airbag is normally folded and housed in the upper edge of windows in the interior of vehicle, and deploys to cover the interior of the windows upon inflow of inflation gas.
2. Description of Related Art
In the prior art, Japanese Patent Laid-Open No. 2000-6747 is illustrative of a head protecting airbag device in which an airbag includes a gas feed passage located in the upper edge side thereof and an inflatable shielding portion located below the gas feed passage for covering the interior of windows upon deployment. The inflatable shielding portion includes a protecting portion and a vertical passage located rearward of the protecting portion. Inflation gas, when flowing in, flows through the vertical passage into the inflatable shielding portion from the lower end of the protection portion.
However, the prior art discloses an airbag with only one protecting portion, and can hardly be applied to an airbag with a plurality of protecting portions.
Japanese Patent Laid-Open No. 2000-335351 and 2000-52911 are also illustrative of head protecting airbag devices in which the protecting portions are configured such that the energy absorbing property thereof may not be affected largely by the position shift of occupant's heads in the horizontal direction.
However, in these head protecting airbag devices, since airbags upon deployment are expanded while inflating, there was a problem of the protecting portion's not being interposed between windows and occupants smoothly.
These head protecting airbag devices also have difficulty in securing vertical shape retention upon completion of inflation because of wrinkles causable in an uninflatable portion arranged in the horizontal direction or in a protecting portion.
Moreover, Japanese Patent Laid-Open No. Hei 9-254737 discloses in FIG. 6 a head protecting airbag device in which an airbag normally folded and housed in the upper edge side of a vehicle includes a window-ward shielding portion for covering the interior of windows, and a roof-ward shielding portion for covering the interior of body member in the roof side rail, respectively upon completion of inflation.
With this configuration, upon inflow of inflation gas, the airbag expands and inflates the roof-ward shielding portion upward while expands and inflates the window-ward shielding portion downward. Therefore, when an impact is applied to a vehicle occupant to shift toward the window in such a situation as side-impact collision, if the moving speed of the occupant toward the window is fast, the occupant may not be protected properly by the window-ward shielding portion.